<template>
  <div>
      <router-link tag="div" to="/" class="header-abs">
          <div class="iconfont head-abs-back">&#xe600;</div>
      </router-link>
      <div 
      class="header-fixed"
      v-show="!showAbs"
      :style="opacityStyle">
          <router-link to="/">
            <div class="iconfont header-fixed-back">&#xe600;</div>
          </router-link>
          景点详情
      </div>
  </div>
</template>

<script>
export default {
    name: 'DetailHeader',
    data () {
        return {
            showAbs: true,
            opacityStyle: {
               opacity: 0
            }
        }
    },
    methods: {
        handleScroll () {
            const top = document.documentElement.scrollTop || document.body.scrollTop || window.pageYOffset
            if (top > 60) {
                let opacity = top / 140
                opacity = opacity > 1 ? 1 : opacity
                this.opacityStyle = { opacity }
                this.showAbs = false
            } else {
                this.showAbs = true
            }

        }
    },
    mounted () {
        window.addEventListener('scroll', this.handleScroll)
    },
    destroyed () {
         window.removeEventListener('scroll', this.handleScroll)
    }
}
</script>

<style lang="stylus" scoped>
  @import '~styles/varibles.styl'
  .header-abs
    position: absolute
    left: .2rem
    top: .2rem
    width: .8rem
    height: .8rem
    line-height: .8rem
    border-radius: .4rem
    text-align: center
    background: rgba(0, 0, 0, .8)
    .head-abs-back
      color: #fff
      font-size: .4rem
  .header-fixed
    z-index: 2
    position: fixed
    top: 0
    left: 0
    right: 0
    height: $headerHeight
    line-height: $headerHeight
    text-align: center
    color: #ffffff
    background: $bgColor
    font-size: .32rem
    .header-fixed-back
      position: absolute
      top: 0
      left: 0
      width: .64rem
      text-align: center
      font-size: .4rem
      color: #ffffff
        
</style>